U.S. patent application number 09/955085 was filed with the patent office on 2002-03-28 for electrophotographic apparatus.
This patent application is currently assigned to Kabushiki Kaisha Toshiba. Invention is credited to Takahara, Kenichi.
Application Number | 20020037181 09/955085 |
Document ID | / |
Family ID | 18777720 |
Filed Date | 2002-03-28 |
United States Patent
Application |
20020037181 |
Kind Code |
A1 |
Takahara, Kenichi |
March 28, 2002 |
Electrophotographic apparatus
Abstract
An electrophotographic apparatus having a development unit for
forming a toner image by developing an electrostatic latent image
formed at a surface of a latent image holding member by liquid
developer, a drying unit for vaporizing a portion of liquid carrier
included in the developer by supplying drying gas to the liquid
developer at the surface of the latent image holding member, a
heating unit for heating the toner image formed on the surface of
the latent image holding member and a transfer unit for
transferring the heated toner image from the surface of the latent
image holding member to a recording medium, further including a
cover for a gas flow path guiding the supplied drying gas to a
heated area of the surface of the latent image holding member
heated by the heating unit along the latent image holding member
and having liquid carrier recovery unit for recovering the drying
gas guided to the heating area thereby to prevent vapor of the
liquid carrier produced at plural locations from leaking out and in
a small-sized apparatus.
Inventors: |
Takahara, Kenichi; (Tokyo,
JP) |
Correspondence
Address: |
OBLON SPIVAK MCCLELLAND MAIER & NEUSTADT PC
FOURTH FLOOR
1755 JEFFERSON DAVIS HIGHWAY
ARLINGTON
VA
22202
US
|
Assignee: |
Kabushiki Kaisha Toshiba
Tokyo
JP
|
Family ID: |
18777720 |
Appl. No.: |
09/955085 |
Filed: |
September 19, 2001 |
Current U.S.
Class: |
399/250 |
Current CPC
Class: |
G03G 15/107
20130101 |
Class at
Publication: |
399/250 |
International
Class: |
G03G 015/10 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 27, 2000 |
JP |
P2000-295270 |
Claims
What is claimed is:
1. An electrophotograpic apparatus using liquid developer
comprising: a latent image holding member to form an electrostatic
latent image on a surface of the latent image holding member; a
development unit which develops the electrostatic latent image with
the liquid developer containing liquid carrier and toner particles,
and forms a toner image on the surface of the latent image holding
member; a gas supply unit which supplies gas to evaporate a part of
the liquid carrier and generate a vapor of the liquid carrier; an
image transfer unit which transfers the toner image from the latent
image holding member to a recording medium; a cover which covers a
part of the image transfer unit and a part of the latent image
holding member; a heater which heats the toner image on the image
holding member or the toner image on the image transfer unit in a
region bordered by the cover; and a recovery system which collects
the gas with the vapor of the liquid carrier from the region,
wherein the gas supply unit supplies the gas to the region through
a first portion of the cover, and the recovery system collects the
gas with the vapor of the liquid carrier from the region through a
second portion of the cover close to the heated area by the
heater.
2. An electrophotograpic apparatus according to claim 1, wherein
the recovery system comprises a liquefaction unit which liquefies
the vapor of the liquid carrier, and separates the gas and the
liquid carrier.
3. An electrophotographic apparatus according to claim 1, further
comprising: a circulation system which circulates the gas between
the gas supply unit and the recovery system.
4. An electrophotographic apparatus according to claim 1, wherein
the image transfer unit comprises: an intermediate transfer body
which is pressed against the latent image holding member, and a
press-roller which is pressed against the intermediate transfer
body through the recording medium.
5. An electrophotographic apparatus according to claim 1, further
comprising: a cabinet covering the development unit, the gas supply
unit, the image transfer unit, the cover and the recovery system,
wherein the cabinet has a hollow portion which has a discharge port
to discharge the recording medium and a suction port to suck the
gas which is supplied to the gas supply unit.
6. An electrophotographic apparatus according to claim 5, wherein:
the hollow portion has two suction ports which are faced each
other, and the recording medium is discharged between two suction
ports.
7. An electrophotographic apparatus according to claim 1, further
comprising: a squeeze roller which squeezes a part of the liquid
carrier on the latent image holding member before the liquid
carrier is evaporated by the gas.
8. An electrophotographic apparatus according to the claim 1,
further comprising: an absorbing roller which absorbs a part of the
liquid carrier on the latent image holding member before the liquid
carrier is evaporated by the gas; and a squeeze roller which
squeezes a part of the liquid carrier on the latent image holding
member before the liquid carrier is absorbed by the absorbing
roller.
9. An electrophotograpic apparatus using liquid developer
comprising: a latent image holding member to form an electrostatic
latent image on a surface of the latent image holding member; a
development unit which develops the electrostatic latent image with
the liquid developer containing liquid carrier and toner particles,
and forms a toner image on the surface of the latent image holding
member; a gas supply unit which supplies gas to evaporate a part of
the liquid carrier and generates a vapor of the liquid carrier; an
intermediate transfer body which transfers the toner image from the
latent image holding member to a recording medium and heats the
region in which the toner image is formed; a cover which encloses a
region bordered by the cover and a part of the latent image holding
member; and a recovery system which collects the gas with the vapor
of the liquid carrier from the region, wherein the cover leads the
gas with the vapor of the liquid carrier to a part of the region
connected with the recovery system.
10. An electrophotograpic apparatus according to claim 9, wherein
the recovery system comprises: a liquefaction unit which liquefies
the vapor of the liquid carrier, and thereby separates the gas and
the liquid carrier.
11. An electrophotographic apparatus according to claim 9, further
comprising: a circulation system which circulates the gas between
the gas supply unit and the recovery system.
12. An electrophotographic apparatus according to claim 9, further
comprises: a cabinet covering the development unit, the gas supply
unit, the image transfer unit, the cover and the recovery system,
wherein the cabinet has a hollow portion which has a discharge port
to discharge the recording medium and a suction port to suck the
gas which is supplied to the gas supply unit.
13. An electrophotographic apparatus according to claim 12,
wherein: the hollow portion has two suction ports which are faced
each other, and the recording medium is discharged between two
suction ports.
14. An electrophotographic apparatus according to claim 9, further
comprising: a squeeze roller squeezing a part of the liquid carrier
on the latent image holding member before the liquid carrier is
evaporated by the gas.
15. An electrophotographic apparatus according to claim 14, further
comprising: an absorbing roller which absorbs a part of the liquid
carrier on the latent image holding member before the liquid
carrier is evaporated by the gas; and a squeeze roller which
squeezes a part of the liquid carrier on the latent image holding
member before the liquid carrier is absorbed by the absorbing
roller.
16. An electrophotographic according to claim 1, wherein the gas
supply unit comprises a first pump.
17. An electrophotographic according to claim 16, wherein the
recovery system comprises a second pump.
18. An electrophotographic according to claim 17, wherein the flow
of the first pump is smaller than the flow of the second pump.
19. An electrophotographic according to claim 1, wherein the heater
is disposed inside the latent image holding member.
20. An electrophotographic apparatus according to claim 1, wherein
the heater is disposed inside the image transfer unit.
21. An electrophotographic apparatus according to claim 1, wherein
the development unit forms the toner image on the surface of the
latent image holding member by electrophoresis.
22. An electrophotographic apparatus according to claim 1, wherein
the region formed by the cover in said part of the latent image
holding member is bordered further by a part of the image transfer
unit.
23. An electrophotographic apparatus according to claim 4, wherein
the intermediate transfer body comprises: a rigid roller, and an
elastic layer formed on a surface of the rigid roller.
24. An electrophotographic apparatus according to claim 5, further
comprising: a link attached to the discharge port, wherein the link
closes the discharge port when a power supply is turned off.
25. An electrophotographic apparatus using the liquid developer
according to claim 5, wherein the suction port is disposed at the
bottom of the cover.
26. An electrophotographic apparatus according to claim 1, wherein
the recovery system and the gas unit are mutually connected.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is based upon and claims the benefit of
priority from the prior Japanese Patent Application No.
2000-295270, filed Sep. 29, 2000, the entire contents of which are
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to an electrophotographic
apparatus, particularly to an electrophotographic apparatus using
liquid developer.
[0003] A liquid electrophotographic apparatus using liquid
developer dispersing toner particles in liquid carrier, is provided
with an advantage which cannot be realized by a dry process
electrophotographic apparatus.
[0004] A liquid electrophotographic apparatus is provided with
following advantages in comparison with a dry process
electrophotographic apparatus.
[0005] 1. High picture quality can be realized since an extremely
fine toner particles of sub micron size can be used.
[0006] 2. A sufficient picture density is provided by a small
amount of toner particles and therefore, the apparatus is
economical and can realize texture comparable to that in printing
(for example, offset printing).
[0007] 3. Toner particles can be fixed to paper at comparatively
low temperature and therefore, energy conservation and high-speed
output can be realized.
[0008] Meanwhile, according to the conventional electrophotographic
technology using liquid developer, there are several problems. One
of the problems is caused by using liquid carrier for dispersing
toner particles. That is, a petroleum species liquid is normally
used for the liquid carrier and therefore, there is a concern of
contaminating the environment.
[0009] There are disclosed electrophotographic apparatus that
contain improvements in regard to the problem of contaminating the
environment, for example, Japanese Patent Laid-Open No. 320619/1996
and Japanese Patent Laid-Open No. 114254/1997.
[0010] According to the electrophotographic apparatus, there is
adopted a system of transferring a toner image formed on a surface
of a photosensitive roller onto paper by electrophoresis in a state
in which liquid carrier is present on the surface of the
photosensitive roller. Further, the paper with the toner image
transferred is carried to a fuser and the toner image is fixed onto
the paper by heat fixing. At this moment, the liquid carrier
absorbed in the paper is evaporated by heat in heat fixing.
[0011] The electrophotographic apparatus is provided with liquid
carrier absorbing chamber for covering the fuser. The vapors of the
liquid carrier produced by the fuser is sucked by the liquid
carrier absorbing chamber and recovered to thereby prevent the
vapors from leaking to outside of a cabinet of the liquid
electrophotographic apparatus.
[0012] Further, according to Japanese Patent Publication No.
17950/1983, a fixing and drying chamber having a paper discharge
port is constituted by an airtight structure as much as possible
and the inside of the fixing and drying chamber is maintained under
negative pressure to thereby prevent a vapor of the liquid carrier
from leaking from a gap of the fixing and drying chamber.
[0013] That is, conventional technology of preventing leakage of
liquid carrier is executed with regard to liquid carrier adhered to
paper.
[0014] Meanwhile, researches are carried out on technology of
providing an image having a higher accuracy by reducing disturbance
of the image transfer by transferring a toner image from a
photosensitive roller to a recording medium by utilizing adhering
force of toner particles.
[0015] According to the system, for example, after evaporating
almost all of liquid carrier present at a surrounding of a toner
image formed on a surface of a photosensitive roller by blowing
drying gas, the toner image is transferred to an intermediate
transfer roller arranged to be in contact with the photosensitive
roller, further, the toner image is transferred from the
intermediate transfer roller to paper by bringing the toner image
in contact therewith. At this occasion, viscoelasticity is provided
to toner particles for forming the toner image by heating the
intermediate transfer roller.
[0016] According to the system, the vapor of the liquid carrier is
produced at two locations of the surface of the photosensitive
roller blown with the drying gas and at the surface of the heated
intermediate transfer roller.
[0017] A method of recovering the vapor of the transfer system
utilizing adhering force of toner particles, that is, the liquid
electrophotographic apparatus producing the vapor at plural
locations, has not yet been investigated sufficiently and, for
example, when mechanisms of recovering the vapor are arranged at
respective locations of producing the vapor, there is a problem
that the liquid electrophotographic apparatus is becoming
large-sized.
BRIEF SUMMARY OF THE INVENTION
[0018] An object of the present invention is to provide an
electrophotographic apparatus which prevents vapor of the liquid
carrier produced inside of a cabinet from leaking to outside of the
cabinet.
[0019] According to a first aspect of the present invention, there
is provided an electrophotograpic apparatus using liquid developer
comprising: a latent image holding member to form an electrostatic
latent image on a surface of the latent image holding member; a
development unit which develops the electrostatic latent image by
the liquid developer containing liquid carrier and toner particles,
and forms a toner image on the surface of the latent image holding
member; a gas supply unit which supplies gas to evaporate a part of
the liquid carrier and generates a vapor of the liquid carrier; a
heater which heats a region in which the toner image is formed; an
image transfer unit which transfers the toner image from the latent
image holding member to a recording medium; a cover which covers
the latent image holding member, and leads the gas with the vapor
of the liquid carrier to the region; a recovery system which
collects the gas with the vapor of the liquid carrier in the
region.
[0020] According to a second aspect of the present invention, there
is provided an electrophotograpic apparatus using liquid developer
comprising: a latent image holding member to form an electrostatic
latent image on a surface of the latent image holding member; a
development unit which develops the electrostatic latent image by
the liquid developer containing liquid carrier and toner particles,
and forms a toner image on the surface of the latent image holding
member; a gas supply unit which supplies gas to evaporate a part of
the liquid carrier and generate a vapor of the liquid carrier; an
intermediate transfer body which transfers the toner image from the
latent image holding member to a recording medium and heats the
region in which the toner image is formed; a cover which covers the
latent image holding member, and leads the gas with the vapor of
the liquid carrier to the region; a recovery system which collects
the gas with the vapor of the liquid carrier in the region.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0021] FIG. 1 is an outline constitution view of an
electrophotographic apparatus showing a first embodiment of this
invention;
[0022] FIG. 2 is an enlarged partial view of a vicinity of a paper
discharge port of the electrophotographic apparatus;
[0023] FIG. 3 is an enlarged partial view showing a first modified
example of the vicinity of the paper discharge port of the
electrophotographic apparatus;
[0024] FIGS. 4A and 4B are enlarged partial views showing a second
modified example of the vicinity of the paper discharge port of the
electrophotographic apparatus;
[0025] FIG. 5 is an outline constitution view of an
electrophotographic apparatus showing a second embodiment of this
invention; and
[0026] FIG. 6 is an outline constitution view of an
electrophotographic apparatus showing a third embodiment of this
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0027] An explanation will be given of a first embodiment of this
invention in reference to the drawings.
[0028] FIG. 1 is an outline constitution view of a liquid
electrophotographic apparatus using liquid developer showing the
first embodiment of this invention.
[0029] First, an explanation will be given of an image forming
process.
[0030] A liquid electrophotographic apparatus 1 comprises a cabinet
29. Inside of the cabinet 29, there is arranged a latent image
holding member comprising a photosensitive roller 2 rotated in a
direction designated by an arrow mark 10.
[0031] A charger 3 is arranged at a surrounding of the
photosensitive roller 2 and the charger 3 uniformly charges the
surface of the photosensitive roller.
[0032] The charged photosensitive roller 2 is rotated in the arrow
mark 10 direction and the surface is selectively exposed by a light
source such as a laser oscillator 19. A charge amount of the
surface of the photosensitive roller 2 is selectively attenuated
only at an exposed area. As a result, there is formed an
electrostatic latent image comprising charged areas (nonexposed
areas) and noncharged areas (exposed areas).
[0033] The electrostatic latent image is successively developed by
a development unit 4. The development unit 4 includes a vessel 4-1
for containing liquid developer and a development electrode 4-2 in,
for example, roller-like shape arranged proximately to the
photosensitive roller 2.
[0034] Further, the liquid developer includes toner particles and
liquid carrier dispersedly holding the toner particles. The liquid
developer is adjusted in a desired concentration and contained in a
liquid developer tank 14. The liquid developer is circulated
between the liquid developer tank 14 and the vessel 4-1.
[0035] The liquid developer supplied from the liquid developer tank
14 to the vessel 4-1 is carried by being adhered to the development
electrode 4-2 in the rotating roller-like shape and is brought into
contact with the photosensitive roller 2. In the liquid developer
supplied to the photosensitive roller 2, the toner particles in the
liquid developer is selectively adhered to the charged area or the
noncharged area of the photosensitive roller 2 by electrophoresis
in accordance with an electric field between the photosensitive
roller 2 and the development electrode. As a result, there is
formed a toner image based on the electrostatic latent image which
has been developed by the toner particles on the charged
photosensitive roller 2.
[0036] Further, as liquid carrier, there is used a liquid which is
nonpolar and having excellent performance of dispersing the toner
particles and normally, a petroleum species solvent such as Isoper
(made by Exon Chemical Corporation) is used. Further, a mixture of
resin and pigment is used for the toner particles.
[0037] Further, according to the electrophotographic apparatus
shown in FIG. 1, there is arranged a squeeze roller 4-3 arranged
proximately to the photosensitive roller 2. The squeeze roller 4-3
is rotated to move in a direction opposed to that of the
photosensitive roller 2 at an opposed portion thereof to thereby
squeeze off the liquid carrier physically. Further, by supplying
the squeeze roller 4-3 with predetermined potential, after
development by the development electrode 4-2, the toner particles
remaining at the noncharged area of the surface of the
photosensitive roller 2 can also be removed from the surface of the
photosensitive roller 2.
[0038] The toner image on the surface of the photosensitive roller
2 formed by the liquid developer in this way, is transferred to an
intermediate transfer roller 7. For example, transfer of the toner
image from the photosensitive roller 2 to the intermediate transfer
roller can be carried out by utilizing the adhering force of the
toner particles. In this case, the transfer efficiency can be
promoted by bringing about a state in which there remains the
liquid carrier of a small amount to a degree of not solidifying
toner particles at a periphery of the toner particles for forming
the toner image.
[0039] For that purpose, the liquid carrier on the surface of the
photosensitive roller 2 is further removed on the downstream side
of the development unit 4 and on the upstream side of the
intermediate transfer roller 7. For example, the liquid carrier is
removed by an absorbing roller 5 or a blowing nozzle 15. The
absorbing roller 5 is formed by a porous material such as sponge
and is arranged to be brought into contact with the photosensitive
roller 2. The liquid carrier on the surface of the photosensitive
roller 2 is brought into contact with the absorbing roller 5 and
absorbed thereby. The blowing nozzle 15 vaporizes the liquid
carrier by blowing drying gas supplied from a wind blowing
apparatus to the liquid developer on the surface of the
photosensitive roller 2 and removes the liquid carrier to a degree
by which there remains a small amount of the liquid carrier to a
degree of not solidifying the toner particles.
[0040] The drying gas used here can be used without being
particularly limited, for example, air or the like can be used.
Particularly, the liquid carrier can further be expedited to dry by
using dried gas or gas at temperature higher than room
temperature.
[0041] Here, the liquid carrier is removed by using two kinds of
the absorbing roller 5 and the blowing nozzle 15 because it is
difficult to sufficiently remove the liquid carrier by only using
the absorbing roller 5 and when the liquid carrier is removed only
by the blowing nozzle 15, a long period of time is needed for
removing the liquid carrier.
[0042] In a state in which almost all of the liquid carrier has
been removed in this way, a toner image on the surface of the
photosensitive roller 2 is transferred to an intermediate transfer
medium such as the intermediate transfer roller 7.
[0043] The intermediate transfer roller 7 includes a rigid roller
and an elastic layer formed on the surface of the rigid roller and
is arranged to be brought into press contact with the
photosensitive roller 2. Further, the elastic layer is subjected to
a surface treatment such that a performance of the surface of the
photosensitive roller 2 for removing the toner particles becomes
higher than a performance of the surface of the elastic layer for
removing the toner particles.
[0044] The toner image carried to the portion of bringing the
photosensitive roller 2 and the intermediate transfer roller 7 into
press contact with each other, is exfoliated from the
photosensitive roller 2 by the adhering force of the toner
particles and is primarily transferred to the intermediate transfer
roller 7.
[0045] Further, a heater 12 is arranged at inside of the
intermediate transfer roller 7 for heating the surface of the
intermediate transfer roller 7 and vicinity thereof. There are two
objects for heating the surface of the intermediate transfer roller
7. One of the objects is to provide viscoelasticity to the toner
particles for forming the toner image. This is for promoting the
transfer efficiency for transferring the toner particles from the
photosensitive roller 2 and the intermediate transfer roller 7 to
an intermediate transfer roller. Other of the objects is to
vaporize the liquid carrier remaining in the toner image on the
surface of the intermediate transfer roller 7. When the liquid
carrier is included in the toner image on the surface of the
intermediate transfer roller 7, the liquid carrier permeates also
into the toner image transferred on paper 11, as a result, the
liquid carrier is discharged outside of the cabinet 29 along with
the paper 11. Therefore, by heating the intermediate transfer
roller and vaporizing the liquid carrier included in the toner
image at inside of the cabinet, the carrier can be prevented from
discharging outside of the cabinet 29 by way of the paper 11.
[0046] The heater 12 for heating the intermediate transfer roller 7
may be arranged to the intermediate transfer roller or may be
arranged at inside of the photosensitive roller 2.
[0047] A press-roller 8 is brought into press contact with the
intermediate transfer roller 7 and the press contact portion is
supplied with a recording medium such as the paper 11. The toner
image transferred to the intermediate transfer roller 7 is brought
into contact with the paper 11 and is secondarily transferred from
the intermediate transfer roller 7 to the paper 11 by the adhering
force of the toner particles.
[0048] In this way, after transferring the toner image from the
photosensitive roller 2 to the recording medium by a transfer
apparatus having the intermediate transfer roller 7.and the backup
roller 8, the toner particles remaining on the surface of the
photosensitive roller without having been transferred, is removed
from the surface of the photosensitive roller 2 by a cleaner (not
illustrated) and a successive image forming process is carried out
by the photosensitive roller.
[0049] Next, an explanation will be given of flow of the drying gas
supplied into the cabinet 29.
[0050] According to the electrophotographic apparatus 1 shown in
FIG. 1, the drying gas (air) is sucked from a suction port provided
at a vicinity of a discharge port 32 of the paper 11 by a pump (or
fan) 21 and the sucked air is blown to the photosensitive roller
2.
[0051] Further, a port of the apparatus from the surface of the
photosensitive roller 2 supplied with the drying gas over to the
intermediate transfer roller 7, is covered by a cover 16 formed
along the surface of the photosensitive roller 2 and forms a space
formed as hermetically as possible by the photosensitive roller 2
and the cover 16. The drying gas blown from the blowing nozzle 15
is guided to the heated intermediate transfer roller 7 along the
cover 16.
[0052] Although it is inherently preferable that the space closed
as hermetically as possible, constitutes a completely hermetically
closed space by the cover 16 and the photosensitive roller 2, it is
permitted that at a vicinity of an area where the intermediate
transfer roller 7 and the paper 11 are brought into contact with
each other and at a vicinity of the surface of the photosensitive
roller 2, gaps are provided between the vicinities and the cover
16. The reason is that it is difficult to set an interval between
the rotatable sensitive roller 2 and the fixed cover 16 into a
completely hermetically closed state. Further, because it is
necessary to bring the intermediate transfer roller 7 into contact
with the paper 11 transferred to outside of the cabinet 29 and
accordingly, a gap is needed at the vicinity of the area for
bringing the intermediate transfer roller into contact with the
paper 11.
[0053] That is, the cover 16 is constructed by a structure in which
the cover 16 is arranged proximately to surface of the
photosensitive roller 2 and the region of transferring the toner
particles to the paper 11 and at other area, gas is not moved to
outside of the cover 16.
[0054] By constructing such a structure, the drying gas and the
liquid carrier can be brought into contact with each other for a
long period of time during a time period from the region blown with
the drying gas from the blowing nozzle 15 and the region arranged
with the intermediate transfer roller 7. And accordingly, the
efficiency of drying the toner image relative to the flow rate of
the drying gas can be promoted.
[0055] At a vicinity of the intermediate transfer roller 7 of the
cover 16, there is connected liquid carrier recovery path 23 for
recovering gas at inside of the space closed as hermetically as
possible covered by the cover by, for example, a suction pump (or
fan) 27. That is, gas including drying gas, vapor of the liquid
carrier vaporized by being dried and vapor of the liquid carrier
vaporized by being heated at the transfer apparatus such as the
intermediate transfer roller 7, is recovered from the liquid
carrier recovery path 23 to liquid carrier recovery apparatus 25
(however, the liquid carrier recovery path 23 is not connected to a
pipe 20 connected to the pump 21).
[0056] The liquid carrier recovery apparatus 25 is arranged with a
cooling apparatus of, for example, a Peltier element. Gas recovered
into the liquid carrier recovery apparatus 25 is cooled by cooling
means for liquefying the vapor of the liquid carrier in the gas.
Further, the liquefied liquid carrier is removed and recovered to,
for example, the vessel 14 and gas removed of the vapor is
discharged to outside of the cabinet 29 by the pump 27 (fan) for
recovery.
[0057] In this way, by providing the cover 16, vapor of the liquid
carrier produced by the heater 12 and the drying gas can be
recovered by a single one of the pump 27 for recovery.
[0058] Further, when gas flow amounts of the pumps 21 and 27 are
respectively designated by notations F1 and F2, it is preferable
that F1<F2.
[0059] In the case of F1.gtoreq.F2, there is a concern that the gas
is leaked from the gap of the cover 16 in the space closed as
hermetically as possible formed by the cover 16 and the
photosensitive roller 2, for example, at the vicinity of the area
where the intermediate transfer roller 7 and the paper 11 are
brought into contact with each other, into the cabinet 29,
depending on cases, further to outside of the cabinet 29.
[0060] According to the liquid electrophotographic apparatus having
such a constitution, whereas when recovery of the vapor produced
by, for example, drying gas and recovery of the vapor produced by
heating the intermediate transfer roller 7, are carried out
separately, two pumps (or fans) are needed, the vapor produced from
two locations can be recovered by the single pump 27 (or fan). And
accordingly, the liquid electrophotographic apparatus can be
downsized.
[0061] FIG. 2 is an enlarged partial view of a paper discharge port
of the electrophotographic apparatus shown in FIG. 1.
[0062] After the toner image has been transferred, the paper 11 is
feeded by four carrier rollers 30a, 30b, 30c and 30d and discharged
from the paper discharge port 32.
[0063] The paper discharge port 32 is provided at a recess port
formed in the cabinet 29. The recess port is connected with one end
of the introducing pipe 20 connected to the blowing nozzle and
formed with the suction port of the drying gas delivered to the
blowing nozzle.
[0064] As a result, an air flow 35 designated by an arrow mark is
formed at a vicinity of the suction port 31 and accordingly, even
when the vapor is leaked from the discharge port 32, the vapor is
carried from the suction port into the cabinet 29.
[0065] By reducing an aperture 31 of the recess port formed in the
cabinet 29, the air flow 35 at the aperture 31 can be increased and
therefore, the vapor can further be reduced from leaking to outside
of the recess port.
[0066] FIG. 3 is an enlarged view showing a first modified example
of the vicinity of the paper discharge port.
[0067] In FIG. 3, there is arranged a paper discharge port lid 41
having a rotating shaft 40 at the paper discharge port 32. The
paper discharge port 41 is brought into a state of opening the
paper discharge port 32 as illustrated at least during a time
period in which the paper passes through the paper discharge port
and during a time period in which the paper does not pass through
the discharge port 31 as in a time period in which power supply of
the image forming apparatus is made OFF, the paper discharge port
41 is moved in an arrow mark 42 direction in the drawing centering
on the rotating shaft 40 and closes the paper discharge port 32. As
a result, during the time period in which the power supply is made
OFF, airtightness of the inside of the cabinet 29 can be maintained
and the vapor is prevented from leaking from the cabinet 29 to
thereby realize the safe and clean electrophotographic apparatus
without contaminating environment.
[0068] Further, by mounting a lid similar to the paper discharge
port 41 to an outer side of the cabinet 29 of the discharge pipe 26
of FIG. 1, the liquid carrier can be prevented from leaking out
when the power supply is made OFF.
[0069] FIGS. 4A and 4B are enlarged views showing a second modified
example of the vicinity of the paper discharge port in which FIG.
4A is a plane view viewed from an upper face and FIG. 4B is a
sectional view viewed from a side face.
[0070] According to the modified example, one end of the
introducing pipe 20 connected to the blowing nozzle is bifurcated
and bifurcated introducing pipes 20a and 20b are constituted on
both sides of the recess port 31 of the cabinet 29 as
illustrated.
[0071] According to the electrophotographic apparatus having such a
constitution, the suction ports are formed at side faces of the
recess port 31 and accordingly, the suction ports are not closed by
the discharged paper 11. Further, since the suction ports are
arranged on the both sides of the recess port, left and right
suction force operated to the discharged paper 11 become uniform
and the paper 11 can stably be discharged. As a result, jamming in
discharging the paper can be prevented and the electrophotographic
apparatus having high reliability can be provided. Although the
suction port is made circular in the drawing, according to the
invention, the effect can be achieved without depending on the
shape of the suction port. Further, although the suction ports are
provided on the left and on the right of the paper discharge
chamber, a similar effect can be achieved by providing the suction
ports at the upper side and the lower side of the paper discharge
port.
[0072] FIG. 5 is a view showing a second embodiment of an
electrophotographic apparatus according to the invention. According
to the electrophotographic apparatus, one end of the introducing
pipe 20 connected to the blowing nozzle 15 is provided at a bottom
portion of the cabinet 29. In the drawing, portions the same as
those in FIG. 1 are attached with the same notations and a detailed
explanation thereof will be omitted.
[0073] A liquid electrophotographic apparatus 50 is provided with
the suction port of the introducing pipe 20 not at the vicinity of
the paper discharge port but at the bottom portion of the machine.
According to the liquid electrophotographic apparatus 50, the air
intake port is disposed at the bottom portion of the machine and
therefore, noise by sucking can be reduced.
[0074] FIG. 6 is a view showing a third embodiment of an
electrophotographic apparatus according to the invention (the same
notations designate port the same as those in FIG. 1 and an
explanation thereof will be omitted).
[0075] An electrophotographic apparatus 60 shown in FIG. 6 differs
from the liquid electrophotographic apparatus shown by FIG. 1 in
that the drying gas is used to circulate the blowing nozzle 15, the
surface of the photosensitive member, the liquid carrier recovery
apparatus and the blowing nozzle 15. That is, the blowing nozzle 15
and the liquid carrier recovery apparatus 25 are connected by a
pipe 24 and the drying gas removed of the liquid carrier component
is discharged from the blowing nozzle again.
[0076] According to the electrophotographic apparatus shown in FIG.
1, the drying gas processed by the liquid carrier recovery
apparatus 25 is discharged to outside of the cabinet 29. Therefore,
it is necessary to use the liquid carrier recovery apparatus
capable of liquefying a large amount of the liquid carrier in a
short period of time to prepare for the case in which vapor of the
liquid carrier is produced by a large amount as in the case of
carrying out the image forming process continuously. As a result,
large-sized formation of the carrier solution recovery apparatus 25
results.
[0077] According to the electrophotographic apparatus shown in FIG.
6, the drying gas repeatedly passes through the liquid carrier
recovery apparatus 25 and accordingly, even when the image forming
process has been finished, by starting the liquid carrier recovery
apparatus, even in the case in which liquefying capability of the
liquid carrier recovery apparatus 25 is comparatively low, the
vapor of the liquid carrier filled in the cover 16 can firmly be
liquefied by taking a long period of time. As a result, the liquid
carrier recovery apparatus can be downsized.
[0078] Further, the pump for supplying the drying gas to the
blowing nozzle and the pump for sucking the drying gas and the
vapor of the liquid carrier at inside of the cover 16 to the liquid
carrier recovery apparatus, can commonly be used and therefore, the
apparatus can be downsized in comparison with the
electrophotographic apparatus shown in FIG. 1.
[0079] Additional advantages and modifications will readily occur
to those skilled in the art. Therefore, the invention in its
broader aspects is not limited to the specific details and
representative embodiments shown and described herein. Accordingly,
various modifications may be made without departing from the spirit
or scope of the general inventive concept as defined by the
appended claims and their equivalents.
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